1987 Celica GT not heating too well!

[porcupinepuffer]

So up here in Canada, winter is just around the corner and I'm noticing my heat in the car is not working as good as it should. In most instances it's simply just the thermostat. I bought a new one which is the basic 180 degree rating, put it in, same thing. Nothing better. I also noticed the existing one was 180 degrees. But anyways, my temperature guage goes up almost halfway, leading me to believe the thermostat is working well within it's specs. I know there were different temperature ratings of thermostats I could get, between 170-195, but I don't think this is my problem. My entire fan speeds are working, but it's just not blowing either hard enough, or enough heat. it's hard to say. It seems to really launch the air out of the front vents. It seems a bit weaker over the windshield, where I really need it to defrost the window. It seems to be a bit hotter towards the middle of the windshield, but all in all, it's just not as toasty as it should be getting. I'm wondering if it's the heater core inside the car? or maybe the hot/cold switch on the controller just isn't moving it over enough. I just don't know exactly where to start to diagnose this and fix the problem. From what I understand, most heater cores are complete nightmares, and big jobs to take out. I don't want to start taking stuff apart for nothing if I don't know what exactly I might be doing or not doing or where my issue lies.

[Bitter]

try flushing it first, read how-to's online.

[MR2Jedi]

After that, check to see if heater core is clogged or possibly an air bubble inside the core.
Bleed the core.

[porcupinepuffer]

Thanks for the replies. I got the problem figured out. One more thing I wanted to check before moving to the heater core with flushing procedures was to make certain the switch mechanism from hot to cold was working correctly. I found out it would try to work fine by the controls, but when I would look under my passenger compartment by the glove box, I could see the motorized arm that would seem to jam when I would switch it back and forth from hot and cold. It would only budge slightly. It was basically stuck in the cold position. When I gave it that extra bit of help with my hand while switching it to hot, it would then move over the full way. Now the heat is working correctly. It's either becoming difficult to open/close with age, or the motor is getting tired.

[RobMilkshakes]

Yeah that seems to be a common problem. I wish mine would have been as easy to track down and take care of. I still have to finally get the whole coolant system burped.

[SouthernGemini]

Checking under the glove box was exactly what I was going to say. I unhooked mine b/c the motor works when it wants and pulling the dash out is not something I want to do. I push the lever forward for heat and back for none.